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Abstract

Tennis leg is the term applied to acute injury of the musculotendinous unit of the gastrocnemius muscle. This injury occurs most commonly following an acute, forceful push-off with the foot of the affected leg. Although this injury has been given the name tennis leg because of its common occurrence in tennis players, tennis leg can also be seen in divers, jumpers, hill runners, and basketball players. Occurring most commonly in men in the fourth to sixth decade, tennis leg is usually the result of an acute traumatic event secondary to a sudden push-off or lunge with the back leg while the knee is extended and the foot dorsiflexed, thus placing maximal eccentric tension on the lengthened gastrocnemius muscle (Fig. 120.1). Tennis leg has also been reported during namaz praying owing to simultaneous forced dorsiflexion of ankle and extension of the knee.The main functions of the gastrocnemius muscle are to plantar flex the ankle and to provide stability to the posterior knee. The medial head of the muscle finds it origin at the posterior aspect of the medial femoral condyle, and, coursing inferiorly, it merges with the musculotendinous unit of the soleus muscle to form the Achilles tendon. Several tendinous insertions are spread throughout the belly of the gastrocnemius muscle, and strain or complete rupture is most likely to occur at these points. In most patients, the pain of tennis leg occurs acutely; it is often quite severe and is accompanied by an audible pop or snapping sound. The pain is constant and severe and is localized to the medal calf. The patient often complains that it felt like a knife was suddenly stuck into the medial calf. Patients with complete rupture of the gastrocnemius musculotendinous unit experience significant swelling, ecchymosis, and hematoma formation that may extend from the medial thigh to the ankle). If this swelling is not too severe, the clinician may identify a palpable defect in the medial calf, as well as obvious asymmetry when compared with the uninjured side. The clinician can elicit pain by passively dorsiflexing the ankle of the patient's affected lower extremity and by having the patient plantar flex the ankle against active resistance.